Control and diversion of exhaust pressure in hydraulic mechanisms



NOV. 1952 F. 'r. COURT 2,619,074

CONTROL AND DIVERSION OF EXHAUST PRESSURE IN HYDRAULIC MECHANISMS Original Filed Nov. 1, 1944 4 Sheets-Sheet l 25, 1952 F. 1'. COURT CONTROL AND DIVERSION OF EXHAUST PRESSURE IN HYDRAULIC MECHANISMS Original Fil ed Nov. 1, 1944 4 Sheets-Sheet 2 PIC-i2 8 as WW We v g INVENTOR. FRANK T. COURT, DECEASED VIRGNIA F.COURT, EXECQTRIX Nov.'2 5, 1952 1 F.v T. COURT 2 ,619,074

. CONTROL-AND DIVERSION OF EXHAUST PRESSURE f IN HYDRAULIC MECHANISMS Original F' iled Nov. 1, 1944; 4 SheetS-Sheet s .sa 5s 7 p I84 I63 l 7/ I I 1: 7! 95 191 6 55, all! laa as 106 as /o/ 9a 170 s [5/ I me f? 10 146' s: I I M w $4 .9 he //0 I. "200 H;

. INVENTOR, FRANK T. coun'r, DECEASED vq n emlA F. COURT, EXECUTRIX NOV. 25, 1952 F COURT 2,619,074

CONTROL AND DIVERSION OF EXHAUST PRESSURE IN HYDRAULIC MECHANISMS Original Filed Nov. 1, 1944 4 Sheets-Sheet 4 M3 INVENTOR.

"T v FRANK T. COURT, DECEASED E VIR NIA ECOURT, EXECUTRIX G V L D I86 I82 I l upon release. is that the actual force required to move the load Patented Nov.

CONTROL AND DIVERSIONOF EXHAUST PRESSURE IIN HYDRAULIC NISMS Frank T. court, deceased,'lat'e ofeMolinepllla by Virginia, Court, executrik,-'Mo1ine,IIll., "assign'or to Deere &' Company, Moline,"lll., 'a'c'orporation of Illinois Original application November 1,1944, Serial No. 561,433. Divided and this application April 4, "1947,Se'rial'No. 739,496

'6' Claims. '1

The present invention relatesgenerallyto hydraulic'power transmitting mechanism and-has for its principal'objectthe provision ofa novel and ifi'iproiled hydraulic'meo'h'anism, which is more sensitively and more accurately controlled than similar mechanism heretofore known to those skilled in'the'art, and yet which issimple and inexpensive to manufacture. This application is a division 'of a'co-pending application, Serial No. 561,433, filed November -l, 1944,'now Patent No. 2,482,249.

Another object of the invention'relates to'the provision of a hydraulic power transmitting mechanism having a manually adjustable control lever for controlling the movements of the mechanism in either direction, the operation of which is closelysimilar to-that of an ordinary manually controlledlever connected directly to a load. v V

In the preferred embodiment of the invention, the controlle'ver moves with the load to an extent which is proportional to the extent of movement of the load. The hydraulic motor moves in a direction corresponding tot-he direction of movementof the control lever by the operator,

and itmoves the load as long as the operator exerts a pressure upon the control lever but when the lever is released, the motor stops immediately. Thus, the operation of the control lever in ahydraulic mechanism constructed according to the invention, is similar to the movement of an ordinary hand lever connected directlyto the load, which moves as long as the operator exerts a pressure against it but stops immediately The only difference in operation is exerted by a separate source of power, rather than by the actual pressure exerted. by the operator.

A system of this type is valuable for the purpose of adjusting agricultural implements associated with a tractor, inasmuch as operators of this type of equipment are familiar with the operation of ordinary hand adjusting levers, so that users of a hydraulic mechanism constructed according to the principles of the invention'would require practically no additional training in its operation.

Still-another object relates to' the provision of anovel and improved hydraulic. control valve, which provides for a more accurate and'positive adjustment of the load by the hydraulic motor. In the operation of a hydraulic power transmitting system, air, oil vapor, and other- 'gases frequentlybecometrapped int'he hydraulic circuit, which introduces a certain "amount of resiliency inlthe circuit which prevents the hydraulic motor from holding the load rigidly in 'adjuste'd position, but'rath'er allows a "certain amount of movement of the loaditotheextent to which the entrapped air'm'ay bepompresse'd. thjeaccomplishment'ofthis object, th'e'valve'i's so designed that as the valve is shifted to stop'the f motor the return duct from lthe motor is "closed 'ofitsli'ghtly before the pressure is relieved from the motor, whereby a'pres'sure is'builtup in the motor duct "circuit which is maintained after the motor has stopped and thus" holds under considerable pressure any trapped gases, thereby eliminating substantially all of the resiliency within the hydraulic circuit. 7

These andother objects and advantages of the invention will be apparent to those skilled in the art after a consideration of the following description in which referenceishad to the drawings appended hereto, in which Figure 1 is a schematic diagram of'the hydraulic circuit; 7

Figure 2 is a sectional elevational view taken through the valve casing, substantially along a line 2-2 in Figure-3;

Figure 3 is a sectional elevational view taken throughthe flow meter along the line -3-3 in Figure 2; V

Figure 4 is a sectional elevational view taken along the line 4+4 in Figure 2 and'show-ing the proportioning mechanism; I v

Figure-5 is an end view of the valve casing as viewed along the line 5- 5 in Figure 2;

Figure 6 is an elevational view of an apertured plate interposed between the valve case and the flow meter,. as viewed from the meter-side of the plate indicated b the line ii-6 in Figure 2:

Figure 7 is ain'elevation'al View of the valve case side ofthe plate as-viewed "along the line "l- -l in FigureZZ;

Figure 8 is an elevational view of the edge of the plate; p

"FigureiQ is a plan view taken in section through the' valve r mechanism, 1 substantially 7 along the line .2 9 inFigure. 5 and extended through the hydraulicmotor fixed rigidly to the valve casing FigureilO is a fragmentary sectional elevationa1 viewtakensubstantiallyalong the line [0-40 -mechani'sm,"similarito Figure-l but' 'd ra'wn to an enlarged scale and showing a remotely controlled hydraulic motor connected with the valve mechanism; and

Figure 12 is an elevational view of the control lever assembly as viewed along the line I2I2 in Figure 11.

Referring now to the drawings, and particularly to Figure 9, reference numeral I6 indicates the frame of the tractor on which the hydraulic mechanism embodying the present invention is supported. A rockshaft M is mounted in a bearing 42 supported on the frame I6 and is adapted to be rocked by power supplied from the tractor engine 2| for the purpose of raising and lowering or otherwise adjusting implements associated with the tractor.

The rocksh-aft 4| is rotated by means of a hydraulic motor in the form of a hydraulic cylinder 55 (see Figure 9), which is disposed longitudinally of the tractor and rigidly mounted on the side of the tractor engine 2|. A piston 56 is slidable axially within the cylinder 55 and is mounted on a piston rod 51 which extends through the end of a cylinder and is slidable within a sealing gland 58 which is threaded into the end of the cylinder 55. The forward end of the piston rod 51 is provided with a fitting 59 which is swingably attached by means of a link 66 to an'arm 6| mounted rigidly on the rockshaft 4|.

The piston 56 is moved by fluid forced into the cylinder 55 by means of a fluid pump 62 (see Figure 11). The pump 62 can be of any suitable conventional type and therefore need not be described here in detail. Preferably, the pump 62 is disposed in the crankcase of the engine 2i and is driven by a suitable power connection with the latter, and receives oil from the crankcase, and forces the oil upwardly under pressure through a high pressure supply duct P. The flow of oil from the pump to the cylinder 55 is controlled by'means of a valve mechanism indicated in its entirety by reference numeral 63 and comprises a valve casing 64 in the form of a casting, through which a cylindrical valve chamber 65 extends longitudinally. Slidably disposed within the Valve chamber 65 is a valve member 66, which is cylindrical for the most part and fits closely within the cylinder 65 in order to block any flow of oil therethrough. The fluid pressure supply duct P is connected to an axially extending duct 67 within the casing 64, which registers with a pair of axially spaced ports 66, 69 in the wall of the chamber 65 on opposite sides of the midpoint thereof. Another axially extending passage 16 is connected between a second pair of axially spaced ports 'II, E2 in the wall of the valve chamber 65, spaced outwardly from the fluid supply ports 68, 66, respectively. An opening I3 is provided in the top of the casing 64 and is connected by a tube 14 with a valve casing I (Figure 2) disposed inside the crankcase of the engine 2|. A ball valve 76 is urged against a port 11 within the casing I5, by means of a spring I6 which reacts against a plug 19 threaded into one end of the casing. The other end of the casing I5 is connected to a duct 96, which conducts oil to the various engine bearings, illustrated by a bearing housing 9|, in which a shaft 92 is journaled. By this means, the main bearings, connecting rod bearings, cam shaft bearings, and any others can be lubricated by the oil returning from the control valve 63. The spring I8 is sufficient to hold a normal lubricating pressure of approximately 35 pounds per square inch in the duct 96. The surplus oil which escapes through the ball valve port I? returns to the crankcase through the exhaust 93. The pressure of the spring 18 can be adjusted by screwing the plug I9 in or out, thereby adjusting the pressure maintained in the lubricating supply duct 96.

The valve chamber 65 is provided with a third pair of axially spaced ports 86, 9|, which are located between the two pairs of supply and reservoir ports 68, 'II and 69, 12 respectively. The ports 86, 8| communicate with check valve passages 82, 63, within which are disposed check valves 85, which are seated in valve seats 86, 81 and are urged into seated relation within the seats by means of compression springs 88, 89, respectively. The springs 88, 89 are yieldable to permit fluid to flow away from the valve chamber 65 but the check valves 84, 65 prevent flow of oil from the check valve passages 82, 83 into the valve chamber 65.

'A pair of check valves 95, 96 are disposed at the ends of the valve member 66 and are provided with valve stems 91 extending inwardly toward the valve member 66. The ends of the valve stems 91 are seated within thimbles 98, which are inserted into sockets 99 in the ends of the valve member 66, respectively. Compression springs I66 encircle the thimbles 98 within the sockets 99 and exert a force outwardly against the thimbles and valve stems 98, 91, and thus serve to center the valve member 66 within the valve chamber 65 as will be seen later.

The check valves 95, 96 are seated within a pair of annular seat members I6I, I62, which are fixed in the valve chamber 65 and define the opposite ends thereof, respectively. The check valves 95, 96 are seated in the outer sides of the seat members I6I, I62 and have their stems 91 extending through the annular seat members into the valve chamber 65. A pair of compression springs I63 urge the check valves 95, 96 against the seat members I6I, I62, which normally close off the ends of the valve chamber 65. The springs I63 are somewhat stronger than the springs I66 and act in opposition thereto to hold the check valves 95, 96 in flrrn seating relation in the annular seats I6I, I62, hence the inner springs I66 are held in compression against the ends of the valve member 66 to center-the latter within the chamber 65. The chambers I64, I65 which are disposed in the valve casing on the outer sides of the annular seat members I6I, I62, respectively, are connected with the check valve passages 82, 83 by short passages I66, I67, respectively, and the valve chamber I64 is connected by a passage I68 to the forward end of the motor cylinder 55.

A flow meter H5 is mounted on the rear or right end of the valve casing 64, the latter being provided with a vertical extending flange II6 which serves to support a similar vertical flange II! on the flow meter II5. A connecting plate H8 is disposed between the flanges H6, H1 and is formed with passages for interconnecting certain passages in the valve case 64 and flow meter II5 as will be described. The flanges '6, l l! and the plate I I8 are provided with registering bolt holes I I9, through which clamping bolts I26 are inserted for the purpose of clamping the flanges and plate rigidly together so that the flow meter H5 and the valve'casing 64 form a rigid unitary structure.

The flow meter 1 I5 comprises a pair of intermeshing-gears I 25, I 26which are-disposed within a pair of cylindrical intersecting-gearchambers I21, I28, respectively. The :gears fit closely within the chambers 12-1, 128 so that theends o'f the teeth are disposed in sliding contact with the cylindrical walls of the chambers. "I'hegear I is journaled on a pair of axially spaced bearing sleeves I29, best shown in Figure 10, the sleeves I29 being pressed in'to sockets I39 in the plate I I8 and in'the-flowrmeter I I5, respectively. Between :the two bearing sleeves I29 thegear I25 is provided with an axially extending threaded aperture 131 (Figure .10), which is adapted to engage an axially extending threaded rod 132, which is'slidable within the sleeves "I29 and engages "the threads in the gear aperture ,IZ3:I. Thesengagemento'f these threads is rather loose, lsothat the thrust of the gear "I25 is .car- .ried .entirely by "the sleeves I29, while rotation of the gear I25 causes the threaded rod I32 to shift axially through .the sleeves I29. The ends I33 of the rod I32 are slightly smaller in diameter than the threaded portion of the rod, and extend forwardly through a passage :I-3'4 in the valve case 64 and vrearwardly through a passage I35 in a tubular extension I36 of the flow meter II5, respectively. Packing glands 131 are provided embracing the ends I33 of the rod to prevent loss of oil from the rod passages I34, I35, and the glands I31 are securely held in place by bushings I38.

The other gear I26 is mounted on a-sho-rt shaft I39, one end of which is journaled in a socket I49 (see Figure 6) in the plate I I8, and the other end of which is journaled in a similar socket (not shown) in the flow meter casing H5. The gear chambers I21, I28 are open at their inner ends and abut against the face of the plate I I8.

The plate H8 is provided with an aperture I which registers with the check valve passage 83 and thereby connects the latter in communication with the gear chambers I21, I28 adjacent one side of the intermeshing teeth of the gears I25, I26. An aperture I46'is provided in the plate II8 communicating with the gear chambers I21, I28 on the opposite side of the intermeshing teeth from the aperture I45. The left side of the plate I I8 is provided with a valve seat I41 around the edge of the aperture I46 and receives a check valve I48, which is urged in seated position by means of a strong compression spring I49 within a check valve chamber I59 formed in the valve casing 64. The check valve I48 is an excess pressure relief valve and therefore the spring I49 is strong enough to hold the valve I 48 closed against normal working pressures in the system. The excess pressure valve chamber I59 is connected to a longitudinally extending duct I5I in the casing 64, which connects with the check valve chamber I94 at the forward end of the valve casing 64., as best shown in Figure 9.

A branch I52 of the duct I5I extends to a second excess pressure relief valve I53 which is disposed within a valve chamber I54 in the valve casing 64, best shown in Figure 10. Thecheck valve I53 is seated in a seat I55 and is yieldably held in seated relation by a, strong compression spring I56, which holds the valve I53 closed against normal operating pressures within the connecting duct I5I but yields to an excess pressure within that duct. The opposite endof the valve chamber 154 disposed in register with -an aperture' l 6 9 in the plate I I8. The apertures I '46, 1 I 89 are interconnected by means ofia-groove f-6I in the plate {-I-IB, thedepth of 'which'is substantially one-half thatbf the thickness of the plate, as best shown in v.Figure '8. {The groove formed in'the side 0f the plate adjacent the flow meter I I5'a;nd-is covered by the flange I11 of the "flow meter. A continuation I62 of the groove I61 extends in an arc about the axis of theivalv'e chamber 195,:as best shown in :FigureB. The end of the groove .162 communicates with an aperture I63 iin'the plate I I8, which is :disposed in register witha passage 164 in the valvecasing "64, which passage leads to the rear :end of the cylinder 55, as best shown in Figure 9.

The valve member 66 is :shown in thed rawings in its neutral position. It is provided with a pair of axially spaced zones or sections 119,111 of reduced diameter, which are actually tapered, as shown in Figures 2 and -9, but are exaggerated in the schematic diagram of Figure 1 for "the sake of clearness. In the neutral position of the valve member 66, the portions of reduced diameter I19, I-1I bridge across and interconnect the supply ports 68, 69 and the adjacent reservoir ports H, 12, respectively. This causes the oil to flow from the supply duct P through the two supply ports 68, 69 along the reduced portions I19, I1I of the valve member 66 and through-the ports 1 I, 12 and ducts 19, 14 into the lubricating supply duct 99. Any surplus oil beyond that required for lubrication, escapes through the ball valve port 11 into the reservoir through the exhaust 93. The oil is locked in both ends of the cylinder 55 to hold the piston 56 against movement therein, by means of the check valves 84, 85, 95, 96, all of which are held in closed position by their respective compression springs 88, 89 and I93. This looks the rockshaft 4| against movement and thereby holds the implement in fixed position except for such flexibility as is provided by the link connections, as explained in my co-pending application mentioned above.

The implement is raised by shifting the valve member 66 toward the left, by means which will be described later. Shifting the valve member 66 to the left closes the supply port 68 and also closes the reservoir port 12 from communication with the check valve port BI and. also acts through the stem 91 to open the check valve 95. The oil now flows from the pump duct P through the port 59, around the reduced portion I1I of the valve member 66, into the check valve port 8|, forcing the check valve open, against the pressure of the spring 99. The oil flows through the check valve passage 83, and since the check valve 96 is held closed by the spring I39, the oil flows through the aperture I45 in the plate II8 into the flow meter. The oil pressure rotates the flow meter gears, turning the gear I25 in a clockwise direction, as viewed in Figure 3, the other gear I26 turning in a counterclockwise direction, carrying the oil between the gear teeth and the gear chambers I21, I28 and discharging the oil through the aperture I46 in the plate H8. The oil then flows through the groove I6I, I62 and through the aperture I63 in the plate and the passage I64 in the valve casing into the rear end of the cylinder 55, the pressure of the oil forcing the piston 56 forwardly or to the left as viewed in the drawings. With normal loads on the piston rod 51, the oil pressure is insuificient to force the check valve I48 open and therefore no oil flows into the duct I5I.

As the piston 56 moves toward the left; the:

oil in the forward end of the cylinder 55 is forced by the piston through the passage I68 into the valve chamber I66. The check valve 84 is at this time closed, but as mentioned above, the check valve 95 is held open by the valve member 66 and therefore the oil flows through the annular seat I8I into the valve chamber 65 and through the reservoir port H and ducts 10, 14, into the lubricating duct 99 and through the ball valve port 11 to the reservoir. The piston 56 can be stopped at any point by returning the valve member. 66 to the neutral position, thereby closing the exhaust check valve 95 and reestablishing the circulation of oil from the supply ports 68, 69 to the reservoir ports 1|, 12.

The piston 56 can then be shifted toward the right or rear end of the cylinder 55 to lower the load by shifting the valve member 66 toward the right, closing off the supply port 69 and blocking communication between the reservoir port 1| and the check valve port 89, and at the same time acting through the valve stem 91 to open the check valve 96. The oil now flows through the supply port 66 around the reduced portion I18 of the valve member 66, through the passage 86, forcing open the check valve 84, and thereby allowing the oil to flow through the opening I66 and through the check valve chamber I64 into the forward end of the cylinder 55 through the passage I68. Movement of the piston 56 toward the right forces the oil from the right end of the cylinder 55 through the passage I64 and aperture I53, around the grooves I62, I6I into the flow meter through the aperture I 46. The oil leaves the flow meter through the aperture I45 in the plate H8 and flows into the check valve passage 83, but since the check valve 85 is closed by the pressure of the oil, the latter flows through the aperture I61 into the check valve chamber I65. As mentioned above, the exhaust valve 96 is open, permitting the oil to flow into the reservoir port 12 and through the ducts 19, 14 and ball valve 51 back to the reservoir. Again, the piston 56 can be stopped at any point in its range by returning the valve member 66 to neutral position, thereby establishing a circulation of oil from the supply ports 68, 69 to the reservoir ports 1|, 12, while the check valves 84, 85, 95, 96 are all closed by their respective springs and by the pressure of oil within the cylinder.

It should be noted that there is no discontinuity in the flow of oil to the bearings 9| through the supply duct 99. Whenever the lift cylinder is stationary, the entire output of the pump 62 flows directly through the control valve 63 to the supply duct 98, and when this direct supply of oil is cut off by the valve member 66 and applied under full lifting pressure to either end of the cylinder 55, the oil from the other end of the latter flows to the lubricating supply duct 96 and is maintained at the comparatively low pressure required for lubrication by the ball valve. Hence, there is never a time when the bearings are deprived of oil under constant pressure of appropriate value.

Although oil is an incompressible fluid, it frequently occurs that air or oil vapor accumulates in such quantities that even with the check valves closed, the piston 59 is not held rigidly in adjusted position, since it can be reciprocated back and forth to the extent permitted by the compression and expansion of the trapped gases or air within the cylinder or connecting ducts. This difilculty is overcome, however, according to the principles of the invention, by the provision of a small amount of clearance between the check valve thimbles 98 and the ends of the sockets 99 in the valve member 66. By virtue of this clearance, indicated by reference numerals I12, I13 in Figure 2, the valve member does not enga e either of the thimbles 98 until after it is shifted far enough to out off communication between the reservoir port 1| (or 12) and the check valve port IUI (or I92) at the opposite end of the valve. The result of this provision is that pressure is established on one side of the piston 56 slightly before the exhaust valve on the other side of the piston is opened. Conversely, when the valve member 66 is shifted back to neutral position, the exhaust check valve is allowed to close slightly before the pressure is relieved from the other end of the cylinder. This causes the air in the cylinder, if any, to be maintained in a compressed state at all times, thereby minimizing the amount of lost motion in the piston 56 when the valve member 66 is in neutral position, with the result that for practical purposes, the piston 56 is locked rigidly in its adjusted position in the cylinder 55.

For example, when the valve member 66 is shifted toward the left to effect an adjustment of the piston 56 toward the left, the valve member compresses the spring 99 associated with the exhaust valve 95, but does not move the latter, since the spring I63 which holds the valve 95 is stronger than the spring 99. The clearance I12 is sufficient that the reservoir port 12 is cut off by the valve member 66 from communication with the port BI and the supply port 68 is also blocked by the valve member 66, causing oil pressure to be applied through the check valve to the rear end of the cylinder 55, while the check valve at the opposite end is still closed. Thus, the pressure builds up in both ends of the cylinder 55, compressing any gases or air that may be there. A very slight further movement of the valve member 66 causes the latter to engage the thimble 98 of the check valve 95 and open the latter, relieving pressure from the forward end of the cylinder 55 and permitting the piston 56 to move forwardly therein. Conversely, when the valve member 66 is returned to neutral position, it disengages the thimble 98 of the exhaust check valve 95, closing the latter slightly before the reservoir port 12 is opened into communication with the supply port 69, whereupon a high compression is established within the cylinder 55 immediately before the valve member 66 is neutralized, thereby locking the piston 56 rigidly in adjusted position.

As stated above, the valve member 66 is maintained in a central position by the opposed springs 99 at opposite ends thereof.

In case the operator does not release the valve member 66 and permit it to move to neutral position to stop the piston 56 before it arrives at the end of the cylinder 55, or in the event that the load on the rockshaft approaches the maximum safe value, the oil pressure on one side of the piston 56 rises to a value sufficient to open the associated excess pressure relief valve I48 or I53. For example, should the piston 56 reach the forward end of the cylinder, the pressure in the rear end of the cylinder rises until the check valve I48 is forced open, permitting the oil to flow through the passage I5I into the valve chamber I64 and past the exhaust valve 95, which is held open by the valve member 66, into the reservoir port 1I. Conversely, should the piston 56 reach the rear end of the cylinder 55, the pressure in the forward end of the cylinder rises, acting through the I53, thereby establishing aflowthrough thevalve.

chamber I54, the aperture Hill in the plate II8, through the groove I6I and through the flow meter II into. the valve chamber 83 through the aperture I45 in:v the plate, and from there through the exhaust valve-96 into. the. reservoir. port 12.

The valvemember 661s shifted by means of a manually-adjustable controllever I15, swingably mounted on a pivot pin I16, the lever- I being. provided with a supporting hub I11.that is. journaled on the pinv I16. The pivot pin is supported on an arm I18, which is fixed to ashaft. I19, journaled in a hemi-cylindrical recess IBIJ-in the valve casing 64, intersecting the valve chamber 65 beneath and substantially perpendicular thereto. The shaft I19 is formed with a. pair of axially extending splines spaced apart to..form a. pinion tooth.I8I, which meshes with one of a. plurality of. notches I82 cut transversely inthebottom of the: valve, member. 66. The lever extends downwardly beneath the pivot pin I16 and receives a, pin; I84, which is rigidly connected to. a short length of flexible cable I85, the other end of which is fixed, as by soldering at I88,-within a socket I89 in the forward end. I33 of the threaded rod I32,,as-b.estshown-in FigureslO and. 11. The cable I85 is provided with alimited amount of flexibility in bending, but is substantially rigid against twisting.- A piece. of piano wire. canbe substituted for the cable I85 if desired.

Thus, by swingingthelever I15 about the. pivot pin, I84 as. a fulcrum, theshaft I19 is. rocked through the arm I18,.to rockv thepiniontooth IN and thusshift the valvemember 6.6 in either direction from the. neutral position.v Swinging the lever forwardly or to they left,. rocks the toothed shaft I-19-in acounterclockwise direction which shifts the valve'member 65' toward the left which, as explained above, causes a. movement of the piston 56 towardthe forward. or left endof thecylinder 55. Similarly, by swinging. thelever I15: to the right, the piston 56 moves-rearwardly in the cylinder 55, thereby rocking. the main rockshaft 4| in. a. clockwise direction. As the piston 56 moves in. the. cylinder 55, the oil flows throughtheflowmet'er, rotating the gear I on its supporting sleeves. I29, causing the threaded portion I3I'to cooperate with the threaded rod I32. to shift the latter in, thedirection opposite to the movement of the piston, 56, thereby causing thelever I15 to swing aboutthe pivot pin I16 with. the handle. ofthe lever moving in the same direction as the piston 56'andat: a speed substantially proportional to-the speedof the piston 56. Forexample, when thelfever, I15" is shifted forwardly about the pivot.l.84,the valve member 66 is shifted forwardly, causing oil to flow through thecheck valve-85i andlthrough the flow meter from the aperture I'45 to, the aperture I46 in the plate I I8, into. the rightend of the cylinder 55, thereby pushing the piston, 56 forwardly or to the left. Rotation of: the flow meter, gear I25 causes the threaded rod I32..to .shift. toward. the right, exerting. a pull through the cable. I85 on the lower pivot-pinIBA, thereby causing the lever I15- to swing in a counterclockwise direction as the" piston 56 moves forwardly;

It will be evident, therefore, that inasmuch, as the-volumeof oil pumped intothecylinder is directly proportional. to. the movement-of thepiston therein and the volume oi oil. isproportional to the'nu mber of, revolutions of the meter-gear I25, it. followsthat. the axial. movement. of the. rod

10 I33. is directly proportional to the movement of the. piston 55 in the cylinder55; Hence, the position of the rod I83" and lever I15 controlled thereby is an indicationof the position of the piston.

The piston 56 can be stopped in any position of, adjustment by releasing the lever I15, Which retracts slightly in a. clockwise direction as the valve member 66 is centered, but the position of the lever I15 provides a visual indication of the position of the piston 56. within the cylinder. When the operator swings the lever I15 rearwardly or to the right as viewed in the drawings, the valve member 66 is. shifted toward the right, causing apressure tobuild. up in the forward end, of the cylinder 55 while the oil in the rear end of the cylinder is discharged through. the passage I64" and through the flow meter, but this time in areverse direction from theaperture I46 to. the aperture I'45'in the plate I I8, thereby turning the gear I25 in the reverse. direction and shifting the threadedrod I32" toward, the. left, thereby shifting the lever I15 by pushing through the cable, I85 against. the pin I84 and swinging the lever about the upper pivot I16, at a speed which is substantially proportional to the speed of travel of the piston 58 rearwardly in the cylinder 55. The pitch of the threads on the rod I32 and. gear I25 aresuch. that the lever I15 travels through a. predetermined. angular range as the piston 56 moves from one end of the cylinder 55 to the other. The extent of. this range of movement of the lever I15 is limited by permanent stops I86, I81 (see Figure 11) in the form of brackets on. the side of the engine 2|, and which support an arcuate guide member I86 having an arcuate slot I81". An adjustable stop I88 is provided with a threaded stud. I89 slidable within the slot I81. A thumb nut 1.90 threads on the stud and. secures the stop in adjusted. position. Theadjustable stop I88. can'be set on the guide I86" to stop the control'lever I15 at any point in its range for the purpose of determining the operating position of the, plow or other implement. It will be noted, however, that. the lever I15 can be moved past the stop I68 by bending the lever slightly inwardly, to. permit the implement to be adjusted beyond the predetermined operating position, or to synchronize the lever with the piston as will be explained. later;

Inthe event that anexcess load is imposed upon the rockshai't. 4i, raising the pressure in the cylinder above the pressure for which" the relief check valves I48, I53 are set, one of't'helatter will bev forced. open, depending upon the direction of travel of the piston 56, thereby bypassing the cylinder 55- through the by-pass duct I5I, Therefore, since the oil continues to. flow through the, flow member II5, the lever I15continues to move until it encounters the appropriate one of the two stops I86, I81, after which the threaded rod I32 swingsthe lever about the stop as a fulcrum to return the valvemember 66" to neutral position. Thusv it is. evident that. even though the operator holds. the controllever I15 in an active position after the loadLhas increased above the permissible maximum value, the valve is automatically shut ofi after. the shortperiod of time required to shift, the-threaded. rod. I32 to the end of its stroke, .after' which no-further. movement of the valve member 66 can be made in that direction, although. it can-be shif-ted in to opposite direction to back the piston away. from the obstruction which hascausedthe excess pressure.

At that time, however, the control lever I15 is out of timing with respect to the piston 55, for the control lever is at the end of its stroke while the piston 56 is at an intermediate position depending upon where the obstruction was encountered. The lever I15 can easily be resynchronizedwith the piston 56, however, by swinging it in the opposite direction to shift the piston away from the load and holding it in the said opposite direction after the piston 56 strikes the end of the cylinder 55, until the lever has been shifted by the threaded rod I32 up against the opposite stop on the casing 64, thereby causing the valve member 69 to be returned to neutral position. Now the piston 55 and the control lever I15 are both at the end of their range of movement in that direction and are therefore back in timed relation.

Although the operation of the hydraulic mechanism has been disclosed with the flow meter, in connection with the built-in cylinder 55, it will be evident to those skilled in the art that the flow meter could be replaced by a simple direct mechanical connection from the lower pivot pin I3 3 to the rockshaft il However, the flow meter I I5 is an essential part of the system when the system is used in connection with a remote hydraulic motor I90 in the form of a piston I9I slidable axially within a cylinder I 92. The piston I9I is mounted on a connecting rod I93 which is provided with a suitable clevis I94 for the purpose of connecting the piston to a load, while the cylinder I92 is provided with a mounting bracket I95, by which the cylinder can be anchored to a suitable support, either on the tractor I5 or on an implement frame which is connected to be drawn by the tractor I5. The forward end of the cylinder I92 is connected through a suitable fitting I99 to a flexible hose I91, the opposite end of which is connected through a fitting I 98 (see Figure 11) to an aperture I99 (see Figure 9) in the side of the case 64 and communicating with the passage I5I. When only the built-in cylinder 55 is used, the aperture I99 is tightly closed by means of a suitable plug 200.

I The rear end of the cylinder I92 is connected through a suitable fitting 29I to a flexible hose 202, the opposite end of which is connected through a fitting 293 to an aperture 294 (Figure 3) in the side of the flow meter case II5, communicating with the aperture I46 in the plate I I 8. The aperture 294 is tightly closed by a plug 205 (Figure 2), when the remote cylinder I92 is not connected in the circuit.

When it is desired to use only the fluid motor I90, the piston 56 is blocked rigidly within the cylinder 55,'preferably by means of a bolt 2!?! (see Figure 11), which rigidly fixes the arm BI to a bearing casting 42. Thus, although pressure builds up within the cylinder 55, there is no movement of the piston 56 therein, permitting full pressure to be applied to the piston I9I in the cylinder I 92.

It will be evident that if the remote cylinder I92 has the same piston displacement as the built-in cylinder 55, the range of movement of the control lever I15 is the same for either cylinder when used alone. That is to say, the movement of the lever I15 will be substantially proportional in speed to the movement of the piston I 9| in the cylinder I92 and the position of the control lever I15 will be a visual indication at all times of the position of the piston I9I within the cylinder.

However, it is desirable at times to use a remote cylinder I92 which is larger than the builtin cylinder 55, or it may be desirable to connect the remote cylinder I92 in parallel with the cylinder 55 and control them simultaneously. Without further provision, however, this would not be practicable, for the control lever I15 would engage the stops I89, I81 long before the parallel connected cylinders 55, I92 had reached the end of their range, for the flow meter II5 moves the lever I15 a distance proportional to the quantity of oil that has flowed through the gears, and obviously the two parallel connected cylinders would require considerable more oil than would one of them alone. The same would be true if a larger cylinder were used at the remote position. Of course, it is possible to remove the stops I 89, I81 and permit the lever I15 to have a longer range of travel when there is more oil to pump, but such longer range of travel might be too long to be convenient, for it might swing the control lever I15 out of reach of the operator, not to mention the necessity for making the threaded rod I32 long enough and the connections from the rod to the lever proper for the longer range of movement.

To obviate these difficulties, provision is made for by-passing a certain proportion of the oil, with an adjustment provided in the by-pass so that only the amount of oil corresponding to the capacity of the built-in cylinder 55 is passed through the flow meter II5, while the remainder of the oil is by-passed around the flow meter. This is accomplished by providing a short bypass duct 2I5 (see Figure 4), interconnecting the two sides of the gear chambers across the intermeshing teeth of the gears I25, I26. The interconnecting passage 2 I5 is provided within an enlarged portion 2I6 of the flow meter housing II5, with a pair of passages 2I1, 2l8 at opposite ends of the interconnected passage 2I5, respectively, disposed in alignment with the apertures I45, I in the plate II8, respectively. Athreaded bolt member 229 is disposed in coaxial alignment with the by-pass duct 2I5, the inner end of which serves as a plug 22 I, which can be inserted into the by-pass duct 2I5 to completely close the same, or can be backed away from the end of the duct 2I5 to permit a limited flow of oil therethrough. The bolt member 229 is supported in a bushing 222, which is threaded into an aperture 223 in the upper end of the enlarged housing portion 2I6 and a gland 224 is provided for sealing the bolt member 229 against leakage of oil. A sealing washer 225 is provided under the head of the bushing 222.

When the remote cylinder I92 is of the same capacity as the built-in cylinder 55, and the remote cylinder is to be used alone, the bolt member 229 can be screwed in until the inner end 22I blocks the interconnecting duct 2I5. However, when a remote cylinder I92 of larger capacity is installed, the bolt member 220 is backed outwardly to open the by-pass duct 2I5 slightly to permit a portion of the fluid flow to be by-passed through the by-pass 2I5. The lever I15 is then actuated until it comes up against one of the stops I86, I91 but if it engages the stop before the cylinder has reached the end of its travel, that is an indication that more oil should be bypassed and therefore the bolt member 229 is backed oif still farther to move the end 22I farther from the end of the by-pass 2| 5. Conversely, if the hydraulic motor I92 travels over its range before the lever I15 engages the stop, the plug 2 2I should be moved closer to the end of the by-pass 2l5? In tl iismanner, theflowof oil through the meter-and the by-passcan be proportionedso that the lever I and the piston l9l travel over their ranges in the same length of time. In the event that the lever I15 and piston l9l get out of synchronism with each other, they can'be' resynchronized by the same method described above in connection with the built-in cylinder 55.

It is not-intended that the invention be limited to the exact details shown and described herein, except as set forth in the claims which follow.

What i's'claimed as the invention of said Frank T. Court, deceased, and desired to be secured by Letters Patent, is:

l. For-use in hydraulic mechanism including a cylinder, a piston movable therein, and duct means connectedwith both endsof said cylinder, respectively, a valve for controlling the flow of fluid through said duct means, said valve comprising a'casing having'a cylindrical valve chamber'h'aving a pair ofaxially spaced ports connected: in communication with said cylinder ducts,.respectively; a check valve' in each of said ducts providing for fluid flow into said ducts through said ports bu-t restraining reverse flow therethrough, said chamber having supply and exhaust ports therein, a valve member slidable axially in opposite directions within said cylinder from a neutral position, in which said supply and exhaust ports are interconnected, in one direction to connect said supply port with one of said cylinder duct ports and in the other direction to connect said supply port with the other of said cylinder duct ports, a pair of exhaust valves at the ends of said valve chamber engageable by said valve member when the latter is shifted axially to admit fluid to either of said cylinder ducts and to connect the other cylinder duct with said exhaust port, there being sufiicient lost motion between said valve member and each of said exhaust valves so that, as said valve member is returned to neutral position from either direction, it disengages the exhaust valve to close the latter slightly before the supply pressure is relieved from the opposite end of said cylinder, whereby said piston is locked rigidly in said cylinder in adjusted position.

2. For use in hydraulic mechanism including a cylinder, a piston movable therein, and duct means connected with both ends of said cylinder, respectively, valve mechanism for selectively directing fluid under pressure into either end of said cylinder and exhausting fluid from the other end, said valve mechanism comprising a valve casing having a cylindrical valve chamber and a valve member slidable axially therein, means for connecting said cylinder ducts with said chamber, a pair of exhaust valves of the poppet type positioned in said casing to control said cylinder ducts and biased to close the latter, said exhaust valves being engageable by said valve member to open the same at opposite ends of the range of movement of said valve member, respectively, said chamber having a port through which fluid is sup-plied under pressure and other ports through which fluid is discharged from said valve casing, said valve member being shiftable in either direction, selectively, from a central neutral position to an active position near the end of said chamber in which one end of said cylinder is connected through its respective duct means with said supply port, and said valve member being engaged with said exhaust valve associated with the other end of said cylinder to exhaust thesamep therev being sufiicient' clear ance-between said" valve member and said: ex-.- haust' valves in said neutral. position whereby said exhaust-valves-are:disengaged. to. close the. exhausting. end of said cylinder slightly before. the fluid pressure from the supply port is cut off by -the valvemember from thetother end of the cylinder as the valve member is-returned tosaid neutral position.

3; The combination set forth in claim. 2 includ-. ingthe: further provision of opposed resilient means betweeneach end of said valve member andthe adjacent exhaust valve-biased to urge said valvemember towardsaid neutral position.

4. In hydraulic mechanism, acontrolvalvedevice comprising acasing having acylindrical v-a-lve chamber provided with supply and exhaust ports, a valve member shiftable in said chamber from-a central neutral position in either direction to vary fluid-transfer relationship between said supply'and exhaust ports, a cylinder duct portin eachend ofsaid chamber, poppet type checkvalves in said cylinder duct ports, respectively, and spring means urging said check valves toward-closed position, said valve member being engagea'ble-wi-th one of said check valves' when said member is shifted in either direction, respectively, there being clearance between each of said check valve and said shiftable valve member when the latter is disposed in said central neutral position so that said valve member is shiftable axially to a limited extent in either direction to vary the fluid-transfer relationship between said supply and exhaust ports prior to engagement of said valve member with either check valve.

5. In hydraulic mechanism, a control valve device comprising a casing having a cylindrical valve chamber provided with supply and exhaust ports, a valve member shiftable in said chamber from a central neutral position in either direction, a cylinder duct port in each end of said chamber, poppet type check valves in said cylinder duct ports, respectively, spring means between said casing and each of said check valves urging the latter toward closed position, said valve member being engageable with said check valve when said member is shifted in either direction, respectively, there being clearance between each of said check valves and said shiftable valve member when the latte is disposed in said central neutral position, and resilient means disposed between each of said check valves and said shiftable valve member urging the latter toward said neutral position.

6. For use in a fluid pressure system including a two-way motor having a fluid chamber and a motor member movable in either of opposite directions therein, and a pair of duct means connected to the chamber respectively at opposite sides of the motor member: a valve assembly, comprising a casing having an elongated cylindric-al valve chamber therein; an elongated cylindrical valve member selectively shiftable axially in the valve chamber from a central neutral position to either of two active positions spaced axially at opposite sides of the neutral position; supply duct means in the casing communicating with the valve chamber intermediate the ends thereof and intermediate the ends of the valve member; reservoir duct means in the casing communicating with the valve cylinder via a pair of reservoir ports spaced axially of the valve chamber, one at each side of the supply duct means and within the length of the valve member; a pair of fluid-transfer means in the casing connectible respectively to the motor duct means for effecting fluid transfer alternately to and from opposite sides of the motor chamber and including a pair of motor ports spaced apart axially of the valve chamber, one at each side of the supply duct means and communicating with said valve chamber within the length of the valve member, said fluid-transfer means further including a pair of check valve means biased to closed positions respectively between the motor duct means and the reservoir means and biased to prevent return of fluid from the motor, each check valve means having an operating element projecting into the path of movement of the valve member; and said valve member, check valve operating elements, ports and supply duet means being constructed and arranged so that when the valve member is in its neutral position the supply duct means and reservoir ports are in communication and both check valve means are closed, and so that when the valve member is in either active position the supply duct means is cut'ofi from the reservoir means and connected to one fluid-transfer means and the check valve means of the other fluid-transfer means is 16 opened by the valve membe to communicate the associated motor port with the reservoir means.

VIRGINIA F. COURT, Executria: of the Estate of Frank: T. Court, De,-

ceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Temple Feb. 29, 1944 

